Huma huma nuka nuka apua a – this is not only the local name for Hawaii’s state fish, it is also the moniker for a fantastic fish for the home aquarium. Also known as the Picasso triggerfish (Rhinecanthus aculeatus), this fish is colorful in terms of both appearance and personality. If you have a community aquarium that contains more aggressive fish, then this fish may be right for you.
Difficulty: The Picasso triggerfish is easy to keep, as long as you’re willing to feed it enough. Too often, aquarists purchase a cute little R. aculeatus, only to watch it slowly waste away. This fate could be avoided if the triggerfishkeeper was feeding his or her fish enough. Try and give the young R. aculeatus food at least three, and preferably five, times a day. Meals should consist of a variety of chopped seafood, frozen preparations for herbivores, frozen mysid shrimp and frozen krill. Adult Picasso triggerfish can live on fewer feedings per day. Just make sure you watch the back muscles and the belly. If either look pinched in, feed more.
Physical description: The Picasso triggerfish is white with a large dark area over the dorsal surface, with oblique dark bands extending from its anal fin base and a dark band over the eyes that contains blue lines. There is also a yellow stripe that extends from the mouth just below the base of the pectoral fin. The Picasso triggerfish reaches a maximum length of around 10 inches. The halfmoon triggerfish (R. lunula) is a species found on deep reef slopes that is somewhat similar, but it has a longer snout and different markings. The Red Sea or Arabian Picasso triggerfish (Rhinecanthus assasi) is the Red Sea version of R. aculeatus. Both of these triggerfish species lack the black markings on the body.
Range: The Picasso triggerfish occurs from South Africa east to the Hawaiian Islands. It is found over shallow lagoon sand flats to at least 70 feet on reef slopes. The Picasso triggerfish is a veritable invertebrate vacuum reported to feed on sponges, stony corals, mollusks, crustaceans, worms, brittle stars and sea urchins. The Picasso triggerfish will also knock off the occasional small fish.
Compatibility: The Picasso triggerfish can be rather congenial as a youngster, but as its body grows, so too does its desire to harm other fish. In fact, adult Picasso triggerfish will hunt and eat smaller fish. The adult Picasso triggerfish can be kept with larger, bolder fish species, such as moray eels, groupers, snappers, large angelfish, surgeonfish, rabbitfish and pufferfish. It is a good idea to house only one R. aculeatus per aquarium, as they are likely to duel to the death. They will also fight with other members of their genus. Other triggerfish often do well with a Picasso triggerfish in an extra-large aquarium, including the pinktail triggerfish (Melichthys vidua), niger triggerfish(Odonus niger) and scythe triggerfish (Sufflamen bursa). The Picasso triggerfish may be picked on by larger, more aggressive triggerfish (e.g., queen triggerfish, Balistes vetula; orangelined triggerfish, Balistapus undulates). The Picasso triggerfish species is not suitable for the reef aquarium. The Picasso triggerfish may eat nearly any motile or sessile invertebrate, with the exception of large sea anemones that have more powerful stinging cells.
Aquarium conditions: The adult Picasso triggerfish can be kept in a 55-gallon species aquarium or a community aquarium that is 100 gallons or larger. The Picasso triggerfish will appreciate crevices or lettucelike faux corals with interstices that it can slip into when threatened. The Picasso triggerfish will also wedge itself in tight spaces at night when it slumbers. Keep the water parameters for the Picasso triggerfish as follows: pH of 8.1 to 8.4, specific gravity of 1.019 to 1.025 and a water temperature of 74 to 82.
Care considerations: The Picasso triggerfish will rearrange rockwork and may bite heaters, power cords and filter components. The Picasso triggerfish will also create depressions in the sand bed by blowing jets of water out of its mouth.
Breeding: The Picasso triggerfish is unlikely to spawn in the home aquarium. The nest-tending male Picasso triggerfish becomes very aggressive in the wild and will even attack snorkelers.